Transesterification of Hypophosphorous Esters - One Step into the Synthesis of Phosphorous-based Surfactant -
Authors:Zoila Luna, Ana Vega
Mentor:Sylvine Deprele, Assistant Professor, Mount St. Mary's College
Major environmental catastrophes such as the recent explosion of the oil rig Deepwater Horizon (April 2010) in the Gulf of Mexico, and the subsequent oil spill, call for drastic measures to be taken. In an attempt to save the local ecosystems, the oil spill was treated with millions of liters of dispersant. In the ocean, oil naturally scatters via storms or currents over time but chemical dispersants accelerate the diffusion process, allowing the oil spill to easily and naturally break down over a shorted time. Our objective is to synthesis original surfactants, (amphiphilic molecules made of a greasy chain and a polar head) for the use previously mentioned. Our synthetical route is based on phosphorous chemistry and involves hypophosphite esters and their palladium-catalyzed hydrophosphinylation with brominated olefins, followed by the reaction with a tertiary amine. Surfactant chemistry relies heavily on the length of the C-C chain and localization of the polar phosphorus moiety within the molecule.
An initial study of the synthesis of long chain hypophosphorous esters is currently conducted by our group. Using the concept of transesterification, we hope to successfully synthesis long chain hypophosphite esters. When 4 equivalents of the hexanol are used, preliminary results have shown encouraging signs of reaction linked to the appearance of small peaks in the GC spectra, and the clear consumption of the starting reagents. Further analysis will be conducted to try to identify the products formed over time. We are currently facing the challenge of using GC-MS and IR spectroscopy to follow our reactions but anticipate to be able to use 31P NMR on a routine basis in the near future.